1. Field of the Invention
The present invention relates to a clamp device of a drill. In particular, it relates to a clamp device of an air drive drill and an air drive drill equipped with the clamp device.
2. Background Art
In the device piercing a hole in a work, an art processing under stable condition of a position and a posture of processing by positioning and clamping the drill on the work has been well-known. (U.S. Pat. No. 3,663,115 (hereinafter, referred to as Patent Literature 1) and U.S. Pat. No. 5,062,746 (hereinafter, referred to as Patent Literature 2))
In Patent Literature 1, a drill for fixing the whole device on the work by operating a cam with a return spring and an air cylinder and enlarging or reducing in diameter of a head and a collet, has been already disclosed.
In Patent Literature 2, a device for fixing the whole device on the work, which a collet of a clamp mechanism enlarges or reduces in diameter under perpendicular pressure driven by a motor around the clamp mechanism connected to a drill unit, has been disclosed.